Power-operated automatic semitrailer



Nov. 28, 1944. R. M. BARNHART ET AL POWER OPERATED AUTOMATIC SEMf-TRAILER Filed March 28, 1941 6 Sheets-Sheet 1 [71787120219 Iafierii/Zfiarmizmii R. M. BARNHART ET AL 2,363,851

POWER OFERATEIS AUTOMATIC SEMI-TRAILER 6 Sheets-Sheet 2 Nov. 28, 1944.

Filed March 28, 1941 N v- 28, '1944- R. M. BARNHART ET AL 7 2,363,851

POWER OPERATED AUTOMATIC SEMI-TRAILER MMWA Nov. 28, 1944.

R. M BARNHART ET AL POWER OPERATED AUTOMATIC SEMITRAILER Filed March 28, 1941 6 Sheets-Sheet 4 Nov. 28, 1944.

POWER OPERATED AUTOMATIC SEMI-TRAILER 6 Sheets-Sheet 6 R. M. BARNHART ET AL Filed March 28, 1941 PatentedNov- 1944 I Q Robert. M; Barnhart, Alhambra, and James S.

Tormey, Temple City,- Calif assignors to Utility Trailer Manufacturing Company, Los Angeles, Calif., a corporation of California I Application March 28, 1941, Serial No. 385,676

18 Claims. "(01.

This invention has reference to semi-trailers,

and relates particularlyto the system or mechanism by which the semi-trailer is coupled to and supported by the towing vehicle, and whereby the trailer is supported when uncoulpled from the y towing vehicle. A general purpose of the invention, in its typical form, is to provide a fully automatic system in which the coupling mechanism, the trailer support, and also preferably the trailerlbrakes, are all automaticallyinterlocked and cooperated; in which the trailer support is powereoperatedpin coordination with the coupling mechanism, andpreferably the brakes; in

v ich accidental separation of the truck and trailer will cause setting of the trailer brakes EL-lld, or. at least, the positioning of the trailer 230-431) 1 p y a byline 3-3 on Fig. 2, showing the parts of the interlockmechanism inthe same position as in Fig- 2; l a r a Figs. 4, 5 and 6 arevertical sections taken as indicated by line 6 6 on Fig. 2, and showing several difierent typical positions of the interlock mechanism;

support in its operative position; and, generally, {provide a system which is highly reliableand fool-proof-a system in which it is almost impossible or highly improbabl that any mistaken manual operation can lead tountoward results.

In some of the typical forms hereafter described .in detail, the trailer brakes are cooperated with the coupler and the trailer support; but the invention envisages the automatic coordinationof a power operated support with the couplermechanism, whether or not the brakes are included in the coordinated system. If the brakes are so included, thentthe power source for support operation is conveniently the same as that for brake operation. However, the power operation of the support, coordinated with the coupler, may the independent of the brakes;

There aremany other objects and purposes of the invention, but those, together with the characteristics of the invention itself will be best 1111- derstood from the appended detailed description of preferred forms of coordinated system. and

Fig. '7 is a detail section taken as indicated by line 1-1 on Fig. 2 showing the parts in the full line rposition of that figure;

Figs. 8 and 9 are 5 lar "views showing the parts of Fig. '7 in different operating positions; Fig; 10 is a diagram illustrating the several parts of the system which effect cooperation be,- tween the trailer support and the trailer brakes, this figureshowing the system as operated by super-atmospheric fluid pressure;

Fig. 11 is a similar diagram showing a system as operated by sub-atmospheric fluid pressure;

Fig. 12 is a similar diagram illustrating cooperative actionof trailer support and brakes in a system involving only a single connection be" tween tractor and trailer;

Fig. 13 is a similar diagram illustrating power actuation of-the trailer support independently ofthe trailer brakes; and I Figs. 14 and 15 are diagrammatic views illustrating typical electrical poweractuation of the trailer support. a 3 r a In the drawings the rear end of a truck frame isillus trated at 20, carrying a usual form of tiltingsupport 2| (in the form of a saddle or fifthwheel member), this support carrying the kingpin 22. When the parts are in normal, locked and towing relation, king-pin 22 islocked tothe forward end of the trailer by a locking mechapreferred details, reference for this punpose be- 1 ing had to the'accompanying drawings, in which: 1

. Fig. l is a longitudinal vertical section showing the rear end of a towing truck and the forward end of a trailer, equipped with one form Of our improved system, in an illustrative and preferred form;

Fig. 2 is an enlarged fragmentary ection taken as indicated. by line 22 on Fig. 1 and showing, in plan aspect, theking pin lock and themechanism. which performs the function of co-operating and interlocking the king-pin lock andthe trailer support; this figure showing the parts in "their normal positions which they assume when the trailer support is raised to the dotted line po sition of Fig. 1;

Fig. 3 is a vertical section taken asindicated ,nism which is generally designated by numeral 23 in Figs. 1 and 2. a In this locked position, the

king-pin is located at some substantial distance back of the forward end 24a of trailer frame: 24,

having passed back to this position through a longitudinal slot 25 in a plate (fifth-wheel member) 26 onthe underside of the trailer frame:

,When the locking mechanism 23 is unlocked to "allow the truck to be disengagedfrom the trailer,

or if for any reason king-pin, 22 becomes freed.

the king pin must-move forwardly a considerable distance with relation to the trailer before the forward end of trailer frame 24 reaches a position toward the rear where the' saddle 7.l'will tilt downwardly to lower the trailer, orwhere the trailer will drop off thesaddle.

Thetrailerhasthe usual reanwheels' 3H and is equipped with suitable movablesupporting means for the forward end of -its frame.- 'As here illustrated the supporting meahs comprises a leg or legs 3| pivoted at their upper ends to the trailer frame on cross-shaft 32 and carrying a wheel or wheels 33 at their lower swinging ends. The supporting legs are shown in full lines in Fig. 1 in their lowered .or operative ,positions, ready to supportthe trailewwhen it is dropped toffizthe truck. The dotted lines in this figure show the supporting legs in their raised or inoperative position ready for travel.

As here illustrated in preferred iformlthelrnenhanism for raising and lowering the supporting legs comprises an interpivoted .pair of 1inks-34, 35, pivoted at 35 to the supporting ..;legs..arid mounted on a transverse operating shaft #31. which is carried on the trailer frame. :operating arm 38 is mounted on shaft 31, and. piston rod 39 is pivotally connected tothe'en'dofarm 38. The piston rod is attached to piston iliinzcylinder 4i, and the cylinder may preferably be pivotally hung, 'as "illustrated, "upon the same *sha-ft -32 which carries snpporting 1egs-'3| In the lowered Operative position of the-si1-pporting legs "theyare somewhat forwardot a vertical j position =-un'dertheir pivot 13-2, so -that weight placed =upon-the-supporting legs tends to move their lower ends further forwardlypputting 'at'ension on 1inks34; 35 and tendingto straighten those links out. The 'links thu's positively prevent further to wardswinging of 'the'support- =in-g legs under load. "Anni iffor -anyreason a rearward "force is brought to 'bear -onth'e -sup porting Y-legs, rearward movement of the legs is Prevented bythe fact that' the lii'iks iirr'th'eir' full =linepositions are slight-l between 36' and "3 'l,"and in'ter 'engaging =stops =l3 prevent the linksi-rom breaking' furtherdo wardly.

Rearward and upward nro-vement of -the sup- -"shown "in*dotted lines in that' figure. iIn this ilatter' osition links- 31 aTid SE make but 'a 'sm'all 45 angle with each other so' th'alt the' weiglit of-supporting legs -3'l has no J great tendency to rotate t'h'e transverse shaifttl. Thisarrangement results in that no great force is necessary to h'old locking dog 54 behind which king-pin 22 is locked. This locking dog swings between the open posi tion shown in dotted lines in Fig. 2 and the closed position shown in full lines in that figure, being held in the closed position by latch bolt 55. The rearward end.of..slot 25in plate 23 forms a limit stop for the rearwardmovement ofwk ing-pin' 22 with relation to the trailer. A finger 553 is intesgrally connected with looking dog 54 and swings with it, so that when the locking dog is inits open position Itheffinger lies in a position across slot '-'--25, a'nd the rearwardly moving king-pin strikes the finger and .moves it and the locking dog to ."the lfiilllline positions of Fig. 2. As dog 54 swings -to-litsz-iolosed.position, the beveled surface 54:; at .itsiouterrend; engages beveled surface 550, of latch bolt 55, pushing the latch bolt rearwardly in its "slide'guide t-l "against the tension of a spring 63 andnvthe Spring then forces latch bolt 55 to its latching position, shown in full lines in Fig. 2, as

soon as'tl'ie locking dog has passed the latch bolt.

The 'ling piniz is thus fully lo'cked in 'draft: relation to the trailer, the forward' end ot the :trailer is lo'ckedin supported relation on trucksadcll'e 21, and these relations cannot be. changedian'd the 'king pin released for -for-ward separative movev ment rrom' the trailer until1latch'bo1ti55 is withy' be'low" a straight line "porting 'legs to the dotte'd line inoperative p'osi- -40 the-supporting legs in their upper inoperative p'os'ition; whether that-force be applied via'piston "Ill-or appliedfiirectly tothe supporting legs "or to 'any otherzpart of-the-supp'ort operating system.

'TWhe locking mechanism indicated at 23 in Figs.

' '1and 2, andthe interlocking mechanism shown e Heinniiller end 'Cha'riles'F. Ro'g'inson 'andissued as-Patent Naif-253051704, "on"'*-December 22, 1942.

Thegeneral function -of these mechanisms, "as will hereinafter appear, is "so to interlock the ne'ith'er 'oan move eexcept under the control of the other.

.ens best shown infifigi'h an upright pivot-pin 53 is-mounted directly or indirectlyon plate '2 8 and "forms the 'pivcit for the "horizontally swinging '75:Ionly ibe'idone' byfloweringthea supporting' legs 3|.

kingepindock and the trailer supporting legs that drawn.

-One arm "62 of "a b'ell crank lever, whose other arm is fid, engages' l'atch bolt 55. .Thelleveriis tpivoted at 6-3 1 and :its, longer arm 64. has an rend Wa which moves back and forthlongitudinally b'etwe'en the -=rearward and iforward tDOSltlOHS SIKJhas shown in full and' 'd'o'ttedrlin'e .:in IFig; 2. :FIEhe "lever end #6411 projects athrough 'ia longitudinal slot-65 in one side 'vvallfifi ofra box-shapedtcasing li'l rand engages an interlock a lider 'fiii' which'sis :guided sin the casing. :Slider :68 is pivotally mounted 1 near "its rear end at 69, Fig- '3,':on .;the forward end of 'coupling rod llifithe'irearwa-rd parts of whi'ch are-"shown in 'Fig; l. The forward end of rod 1 Ill iyguidedwby passing through. an aperture ll *in'lth'e rear wall of' bo'x c'as'ing fil. 'In the preferredarrangement-here illustrated. the rear 'end'lof rod =lllfisi'connec'ted, vialan :ad- 'justa'ble connection :at 'JUQ' Wl IhYaJPlVOt1311142 on the end "of an? arm "'lr3fwhi'ch is "rigidly' mounted on the same JIJiVOtIShJftY-iy that-forms the axis of'and turns with the swingingsupport l-eg r3l. Thus, coupling frod 1U, andrslider :68, "are ztheir forward positions "when the supporting legs are "in their operative forward and loweredpositions and areintheir rearward-positions (Fig. 3) when the supporting legs-arein vtheirrearward and upperdnoperative:po'sition (dotted lines ips-Fig; =I) =When the trailer support is E'inoperative, raised and to the rear, and'the king .pinis locked to ithe, trailer, the %locking mechanism is in therposition shown in 'full lines "in-Fig. Z'and theinter- :lock slider is \in' the {position shown in Fig.-.:3. In this'position's'lider $8 is to the rear i'and't'the end 64a of arm 64, :then in its rearmost position 'inslot--:65,,engages the. forward end a of the longitudinal slot-90 in slider sll. In this position the slider is supported by the leafzspring'filyand the 1 lower :rearwardly sloping 'wall 9% :of slot 90 .is'fpre'ssedwup against arm end 54a. .'Arm zifi lfis yieldingly held in 'its' rearmost'positiontby the rather strong spring fi ll which is attache'd to that zarm-and also to 'the arm' 92fof-a :lo'ckin'g' lever rwh'ose function-willtbe 'afterwards'rdescribed. i'orderrto 'move varm 64 (forwardly iandto retract lock ib'olt 551torlease :lockin'g *dog'rli l it :is' nec'essary to move slider 68 forwardly, and that roan Thus, as long asthe trailer supportis not lowered king-pin 22-cannot be unlocked.

Furthermore, forward movement of slider 68 i and lowering movement of the trailer support to operative position, are preventedby the manually w releasable lock shown in Fig. 2 and designated generally by the numeral 15; As here illustrated in preferred form this look comprises alocking pin 16 which is normally pressed by springfl'l in a direction to enter its end intoa socket ls in slider 68. The outer end of locking pin'lfi is connected by link 19with a manually operable handle 80 pivoted at 80a on the trailer frame. i The extreme end of locking pin 16 is beveled as shown at 16c, and the mouth of socket 18 in theslider is correspondingly beveled as shown at 18c. A dogging plate BI is pivoted at 81a to the trailer frame and has an aperture in its outer endthrough which handle 80 passes,as shown in Fig. 7;. .Outwardmovement of handle 80(to or toward the dotted line positions shown in Fig: 2,

and toward the left in Fig. 7) tends to lift the end of locking pin lfiout of socket 18. In order being cannot move inwardly and I handle 80 is j thusheld in position 8nd" or thereabouts. In

this positionof the parts, handle 80 and locking pin 16 can movewinwardly to reinsert the end of pin 16 in socket 18 whenever slider 68 moves rearwardly again tothe normal position shown in i i Fig. 2, locking pin 16 being constantly impelled inwardly by spring 11. And when the parts do thus finally move back to the position of Fig. 2,. dogging plate 8| i'rnmediatelydrops to its initial ,and norrnalposition of Fig. '7.

. u'Ihe general functi'ons of the manual locking mechanism, as thus described, are first, to lock slider68 positively in its normal (rearward) .position in which'it positively prevents unlocking of the king pin (by preventing release movement of latch55) and in which itprevents (by direct mechanical connection, as here shown) thelower .ing of the trailersupport to its operative position.

None of these parts can be moved without first releasing the manual look. And, as will appear,

, the. king pin cannot thereafter be unlocked until after the trailer support has been lowered. The

tomove handle 80 outward it is necessary to lift dog 8| so, as to lift its shoulder 8|a above the out-- ward path of handle 80. See Figs. and 8.

The operator willlthus liftdog 8| with one hand and hold it up in: a position where the dog shoul" der Blb engages the under surface of handle 80,

and then with the other hand he can move handle 80 outwardly, under the dog shoulder 8Ic,

until the handle engages thedog shoulder Bid at the outer end of the opening in the dogging.

plate. This position of the handle is shown in Fig. 8 and indicated by the dash-dot lines designated 80d in Fig. 2.1 In this position of the handle the extreme end 16a of locking pin 16 is entirely out of socket 18, so thatin this posi- -tion of the handle the slider E8fcouldmove longitudinallywithout engaging the locking pin at all. However, the operator must perform other manual lock is thus the initialcontrol of all the cooperative unlocking operations (including brake operation, as will appear). And the manual lock is of such a nature that a deliberate, two-handed,

operation is necessary to set it to unlocking position, so that it is not likely to be set except by one who knows how, and not unthinkingly by him,

Second, the functioning. of the manual lock is such that the operator sets it (unlocked) in such condition that subsequent .movement of slider 68, when the trailer support is lowered,resets the locking mechanism in potential condition to automatically 1 0M119 slider whenever it comes back to its initial position. And, as will app ar, this operations before he can disconnect the truck from the trailer, and consequently he must be i ableto leave locking pin l6 insuch aiposition relative to .slider 68 that the slider cansubsequentlybe moved forwardly, without the operator holding the locking pin out. so, having retra-cted the locking pin bymoving handle 80 out to the described. limiting .position the operator then moves dogging'plate 8|? upwardly on its pivot until the. lower shoulder 8l'e presses up against the under face 'ofhandle 80', whereupon hereleases handle 80 and spring 11 thenmoves cannot occur until the trailer has again been raised on the tractor, the king-pin locked in place, and the trailer support then finally raised. As

. will appear, it is impossible to move the slider back toits rear position until the other parts are all in proper positions to tow the trailer; and then i the manuallock operatesautomatically to look all the parts in those positions, WlthOllll, any attention from the operator.

As the supporting legs move downwardly and forwardly slider 68 first reaches the position shown in Fig. 4. In thisposition the slider has moved forwardly, and upwardly underthe infiuence of spring 9|, so that the arm end 640. is

then caught in the forwardly facing hook 900 at the handle inwardly to such a position, as shown in Fig. 9 and as indicated: in dotted lines at 80) in Fig. 2, when the handlecatches inthe hook 8 i 7 in the dogging plate. The operator can then leave'thehandle and ,the dogging plate in the the rearward end of the sloping lower wall 9% of slot 90. As the slider then moves further forwardly, arm 64 is moved forwardly with it against the tension of spring 60... Slider 68 moves 01f spring 9! but is temporarily supported during this final forward movement by its hookyengagement position. of Fig. 9 while he attends to theunext sequential operation which results in loweringthe supporting legs and moving slider 68. forward.

In this position the locking pin: 15 has been let back into socket" by a distance not more i than the length of the beveled surfaces Ilia. and

18a. Slider 681 can then moveforwardly, as it is not then positively locked against forward movement by locking pin 16, butin moving forwardly it pushes locking pin I6 outwardly a short 1 distance, handle 80 moves outwardly far enough to disengage from dog hook Blf, and the dog immediately falls to the position of Fig. 8, with handle .89 in substantially the position of that figure (80d in Fig. 2) The extreme end of; locking pin 16 is then riding; on sidesurfacelifla of slider. 68,. so that, the'lockingpin for the time.

with the arm. (Thus, in its. forward movement slider 68 finally reaches the forward position shown in Fig. 5 atthe timesupporting legs 3| reach .their final trailer-supporting position shown in full lines in Fig. 1. i

The parts of the interlocking mechanism are then in the positions shown in Fig. 5, and arm 64 andlatch bolt 55 are in the positions shown in dotted lines in Fig, 2. In that posltion'of latch bolt 55, the inclined surface 551) at its outer end is adapted to be engaged by tip 54?) of locking dog 54 as the locking dog swingstoward its open position shown in dotted'lines in Fig. 2. Thus, with the parts in the positions just previo'usly'explained, and with the; trailer braked (its-braking in cooperation with lowering of the supporting legs is to be described), kingbolt 22 willmove for v positions. ately causes the locking arm 92a to enter slot 102 war'dly relative to ithe trailer when the tractor drives forwardly,ulocking adog 54 will beswung 'from'-its'full line positionito :its dotted line posi- 'ti'on iin 'Fig; :2, and' latch :bolti55 will momentarily beipushedback slightlyibeyondathepositionwshown :inidottedxlines in Fig. 2,1as the locking dog passes ..'it. 'Thistemporary displacement of :thelatchbolt fthrowsarm 64 momentarily-a short distance to the left of the :dotted line :position in Fig.2 and Jitswend "64a moves to theileft from the; position shown in Fig. .5 to that .shown .in .--idotted\ :lines in Fig. 6, removing :its end from book 1900. "Slider 68 is thus released to swing-down to the-position shown in Fig.6 where the upper wall .90e of slot-p98 rests on arm'end 64a. Immediately this :occurs, spring '60 "moves arm 64 back to the .position shown :in full 'linesin Fig. 6,'which,is the normal position shown in 'full lines in -Figs;=2 and Also latch bolt 55 is now back in its normal latching position shown in full lines in but 1 is now held in that position only by spring BlLas slider-fit remains in the forward position shown in :Fig. G-until such subsequenttime assupporting 'legs 32 are raised again to their inoperativeposi- ,tion'.

lfsslider hook 900 and'its function be omitted ifr'om the interlock mechanism, theiaction .0f the slider in moving forward will'still be to release the-coupler look so that itncan be opened by hand orotherwise, although thesliderdoes not ac't'posi- Ztively to open the .lock. The other interlocking {operations remainfthe same as have been described; that is, the coupler-lock is held closedas i-longas the support is inoperative and is released only when the support isin itsoperative position.

- Yposition. Inthe arrangement and design illus- -trated=in=Fig 2 this locking device includes a bellcrank lever pivoted at l ill? and-having one arm92 'engageable by the rear side of finger 56. The

other arm 92a has an end adapted to be pro- 'je'cted throughopening "ml in wall- 660f slider casing 61, and adapted toenter a-slot H12formed iinslider 58 when the slider is finally in theifo'rward position shown in Fig. 6, after king pin 22 has been withdrawn. In the particular design as here shown, slot m2 is formed inapart o'f slider -58 which extends to the rear of slider: pivot ESQ, and asa consequence the :lockingairmQZacannot enter slot 22 until sliderfit'hasdropped from the :position shown'in Fig. 5 to the position shown in i :Fig. 6. As explained before, thatdropping of the -'slider is caused by the .forward removal ofk-ing pin 22.

And looking lever arm, 92 cannot be moved forwardly by spring 60 until the king pin is removed and finger-56 thrown forwardly. The .king. pin cannot be removed until lever arm 64 reaches substantially its 'forwardmost position,

with the supporting legs 3! in their operative So, removal of the king pin immediin the slider; to lock the slider and prevent the return of .the trailersupport -to its raised inoper- .ative position, until the king pin'has -been reinvLserted. *Slot, m2 is a little larger than is :necessary .for reception of locking arm 92a, in .order'to .allow some leeway. and -to'be certain that locking arm "92a.. wil1 move to 'its looking position even' though :the supporting legs have :not been moved fully to the final: supporting positionsqshownein full ylines -in -Fig. 1. vIf the supporting legs have been moved downwardly; and. forwardly to :a position;'just--a-head of a :vertical line they will .support thetrailer and will take theirfinal forward position when weight is imposed upon them. The relation, of slot l-ll2,-to locking arm 920i issuch that, after docking arm 192a enters, the.-slider ;68 cannot-bezmoved rearwardly far'enough-to throw "supporting legs'taI back of. approximately a vertivcal .line,-preferably not back to, thevertical line.

:And therelations of latch bolt 55 to lockingdog *54, ,and-;the slider impelled movements of lever arm 64, are "such: that dog 54 cannot move for- -zvvardly-.past zlatch bolt 55 until supporting legs .3 I

have passed avertical line intheir forward movement.

It maybe remarked that it is preferable-to -lock.slider 68 its forward position only upon removal of the king pin, and not immediately after'the slider reaches its foremost position as -shown'in Fig. 5 and before the king pin is-removed. If the slider were locked in its forward position immediately on reaching that position, it .would be necessary for the operator to remove and then reinsert the king pin before the trailer support could be raised. By providin only for lockingwthe slider after it has reached its forward position and also after the king pin has been removed, it is possible for the operator to re-raise the trailer supporting legs at any time after lowering themand before he. removes the kingpin.

We also remark that, in the sequence of functions necessary to the type 'of interlock and to the typeiof the .whole combination here being described,it is not necessary that the latch bolt "55 be released from its king-pin-releasin-g position ('dottedlinesin Fig. 2) 'by virtue of the out- :ward movement'of the king pin. It is only es- :sential that. the latch bolt be released by some movement of the king pin which occurs before uthe-ping pin reaches its final position on reinsertion; in order that the king-pin shall be finally locked before'the support can be raised. Byzthe foregoing described functions of the interlocking mechanism-the kingpin is locked to the'trailer at all times when the trailer support is not in its operative trailer supporting position. and the trailer support is locked in its trailer supporting position at all-times when the tractor is not fully-locked in trailer supporting position, ass'hown in Fig. 1 and in full lines in Fig.2. -As' lon'g as the king pin is :out of that operative locked position, locking dog 54 and its finger 56 remain in the position shown in dotated lines in Fig. 2 (a spring 540 preventing ac 'cidental displacement from that position), latch bolt 55and. lever arm-164 remain in the position shown in full lines in Fig. 2, and slider .68 remains in the positionshown in Fig. 6, locked bylockingarm92a. The slider can only be un- :locked to move toward the rear and to allow the -trailer support to be raised, by swingingxthe locking clog finger 56 back to the full linetposi- 'tion-of Fig. 2. This can only be done by re? inserting the king pin to the position shown in full lines in Fig. 2. And the insertion of the king pin to that position throws locking dog 54 past latch bolt 55 to the full line position of Fig. "2 where the locking dog is latched to lock the king-pin to the trailer.

:It will be understood that-it is impracticable {l'f not impossible to 'make the parts of "the intera lock to such nicety that locking arm 92a will clear slider 68 just.as the king pin reaches its final position andas locking dog 54 passes behind latch bolt 55. Some leeway might be allowed bygiving theking pin room for further rearward movement in slot 25 after dog 54 passes latch 55; but that would entail an undesirable looseness in the king pin coupling. i l

The mechanism as described overcomes the difliculty. The relations aresuchthat locking arm 92a is withdrawn clear from slider 68 at a point in the movementfofdog 54 when itha's passed the high point on the end of the latch bolt and before the kingpin has reached its rearmost position. If the king pin is left in such,

a position, with 92a just withdrawn, thendog 54 holds latch bolt 55 outand holds arm 64 for ward. Arm 64 then either holds slider 68 to preventraisin-g of the supporting legs, or if the supporting legs are forced up, the enforced rear? ward movement of arm 64 forces the latch bolt home, and the beveled latch face 55b forces dog 54 and the king pin to final lock position. i

If, the king pin has not been backed in far enough to pass the high point on the latch bolt, then of course the legs are held locked in operative position to support the trailer if the truck pulls out from under However, if on the other hand the operator then backs the king pinnclear A home, the previously applied pressure will move the legs up as soon as the interlock is released. The cooperationof the brakes and the brakeoperating system with themechanism which operates the trailer-supporting legs will now be explained. cRearwheels 30,Fig. 1, ofthe trailer are equipped with brakes I 10 of any suitable type and kind and operated in any suitable manner.

As illustrated here in Fig. I (for afluid pressure 1 system) the brakes are set by downward movement of brake-operating rods ll|,which are moved downwardly by application of pressure to diaphragms H2. diagrammatically. Support-operating ucylinder 4|, piston 40 and rod 39 have already beenmentioned. Movement of piston 40 to the right in the diagram of Fig. 10,}corresponding to the movement of that piston downwardly and to the right in Fig. 1, lowers supporting legs 31 totheir operative position. Movement of the piston in the opposite, direction raises the legs to their inoperative position.

"In any of the usual pressure-operated brake;

systems, the tractor or truck is provided with some suitable source of air or other fluid pressure (not shown here) and that fluid pressure is conducted througha supply line H5 (see Fig. to a point near the rear endjof the truck where it is connected by a disconnectible coupling H6 to the pressuresupply line 101113116 trailer. The truck also has a serviceor control line I I8, controlled on the truckby a suit-, able brake control valve (not shown here) and which functions to vary the pressure in theserv-j ice line to operate the brakes; The usual ar rangement is such that when the full fluid pressure is present in the service or control, line the brakesare released,,the brakes being applied by reduction of service line pressure. Theservice line H8 on the truck isconnected with service ,line l onthe trailer via a disconnectible couplirigi la. Shut-off valves, such as shown atlZi in Fig. 1, areusually provided at the end, of the truck linesadjacent the couplings, andhoses such shown at I22 form flexible connections, be

Fig. 10 shows the system tweenithe couplings and: the lines on thefltrailer.

In ausualpressure operatedsystemlthetrailer i supply line H I leads through 'a check valve I25 to servoir I25 and tothe triplevalve I21. ,From

va1veWl 2lla 1ine or, lines 128; lead to the diaa phragm chambers llZa. Thelgeneral function of valve 121 is to apply pressure from supply line 'I ll,]orf,i-rom reservoir (I26 if thesupply line a I is disconnected at ll5,-tof.the diaphragm cham- 19 bers-toset the brakes whenever pressure is, re-

ducedin service line, i 20;and"to exhaust pressure from} the brake-operating diaphragms to'release the brakes. when pressure is th ough service line 120. l

The form oiivalvejliTas here shown ismerely diagrammatic, Tand typical, Pressurel appliedthrough service line l2D""is exerted on the right handem or awediapmagm' 130 to move 3 the 2 phragms. MInuthis brake releasing pOSltlOIL of viaqpassage'jlsa'.to 'tl leTleft-liand side of diairagfm' 130,, and; with equal, pressures applied movesjand holdsthe' leftl; upengreaucuen iswa e a b idefofffdiaphrag on the left-hand side ,orthat I diaphragm tewardithefright. s rt"! are ismovdout oflregistefwithjat mespherie port I32,: a supply pressure por m pllragm aridvaivd to the pressure in! service line pressure on thdjrightlines]. ,1 28"'1eadingi to the brake diaphragm charm. her-sitesetTthlWakesL 1 I '1 he.brake operating, and control, system which h penjdscribdisitypipai or systems which are 1 it is a, eatureiesourpre e t jinyentionl being describedfenfoperated by sub atmospheric the r snt-ha d end M re n-o a g cvlin erM :ename edbri e t le t v to s valve physically incorporated in 1 the structure of p avalve 12 itish eshownas ph s y: separate; for i'clarity of illustration and descrip-, tion. By virtue of this. connection lflw pres sure is applied ,tothe right-hand sideof piston 40, toraise or tend to raise supportinglegs 3| at 1 all times that pressure is present in supply line is Ill. Under normal operating conditions presi sure isalways present inthat supply line except 0 when coupling H6 is disconnected preparatory to uncoupling thetrailer from the truck and while the trailer reinainsuncoupled from the truck. I The left-hand phragms under control of valve 121. Thus, the system is such that whenever from any of vari- 7,0,

also applied to the left hand end of cylinder 4,!

i to move, or tend to move piston 40 toward the right and thus to lowersupportinglegs 3|. 7.5

aagain] applied o? opposite sides of I are diarihfagmfspring I35 I30 s reduced, and the l that movement is uncovered and putpintojcommuni ation with 1s idapablel oflapplication te lthese' com; t secr te iseeese ms e h i erated bysuper-atrnospheric pressure as is new,

p yr ll" :ahea v g w riia l .12 t: y be -1 remarked that in some {systems this check endlof leg operating cylinder 41 is directly connected by; a line l28a withthe line I28 which applies pressure to the brake diaous controlling causes, brakesetting pressure is 1 applied to the brake diaphrag ms, pressure is h general cooperative functions or all the a cooperating and;

A Y interlocked mechanisms are now to be"describedi i" "r drop' the trailer "'thedriver goesthrough" the usual operations of gjtting'the trailer into the chosen position and then setting thebrakes." By'doing that he has applied pressure to theleft hand end of cylinder 41; simultaneously with brake setting, Pressures'arefthus balanced on piston All; and the" supporting legs" are held el'e preferable that'lock l be"first" releasedi When the lock isrelea's'edjthe weight of "the Iegsmayormay not" be" sumcien't' to" forcedocking pin 16; out'iofs'ocket 1'8; if'so; the legs then'd'roptoor near a" vertical hanging position; ifn'ot; thedegs' still remainelevated'T until} the hose coupling H6 5:.

on the supplyline is broken. Immediately that is done, with lock 16' released; pressure is" ex'- hausted from the right hand end" of cylinder 41- andthe' pressurea't the left side of piston" Mim mediately' forces the" piston to the right and." moves thejl'eg's to'tlieir fully operativeposition;

When the legs reach. that. position the king pin lock is unlocked as'beforefexpl'ained; The-tractor can then be drivefiaway;

If the operator shouldbyanycliance forget to release'lock 15' hewill beunableto pull the" king pin away from the'tr'ail'er," even though' he has brokenthehose' couplings. If, on'the other hand he should" release" lock-15* and overlook breakingthe'couplings; he still cannot drivethe tractoraway from-the trailerunlessthe legshave fallen by their' own" Weight to'thefullyol erative' position which" will move slider 68 far enough forward" to release=the king pin look; And. if he should drive the tractor away under those" last mentioned conditions; a the hose connections--may"be made of such-length that they willbe pulled-apart amt-the legs forcibly held by air pressure-in' their flnal positions before the forward end of thetrailer drops ofi the tractor saddle- 21. This last a provision, however;--is: not usually made, the kingpin look under no cirzgsesgssr are still rem-m their lowered operative positionby" air' pressure on the left hand side' of pistonto I 'When coupling" HQ is coupled and its valva opened, the immediate action may depend upon the position in which the I operator has set=the brake control valve in the cab of' the truckf If the controlvalve has been set to exhaust pres-= 1 sure from service; line 126' and to'set the tra'iler brakes, then piston I ML and the supportingalegsl will remain for the time being in their lowered operative position. But" if: the brake control valve hasbeen. set in position toadmit pressure to. service line 520, triplevalve l2! will immediately act to exhaust pressure from. the' brakediaphragms and: also from T the leftahandf side of piston 48. Thebrakes will. thus beimmediately releasedi and' the supporting: legs-simultaneously raised to their inoperative position. If the operas" tor'setshis brake control valveto brake release ing' position after. he.- has coupled up' the="hoses, the raising' of the supporting. legs willJ' be. simul-:

. taneous" with the action of trailerbrakevreleasei which is preparatory-to drivingaway.

And when the supporting legs have? oncei-be'en; raised to their inoperative position and; interlocking-slider 68: once drawn back toaits-normal positionshown: in Fig. 2;-then i-theilock: 1. 5 auto; matically locks the slider; andthe supp'ortin'gg legsx'in their rearward positions; When. onc'e s'o'z locked, subsequent manipulation: of thel brak-t ing system to apply the trailer brakes; during. travel: cannot: cause or allow the' lowering." of? the; supporting legsv to their" operatlvei positions;v

becauseof the lock 917'151; Andr it is-'also.-i1n.' portant to note that, as long as'the; trailer is; coupled; to the truck-,, the pressure fromzisupplyl line- I M constantly tends to hold the; supporting; legs up; and the intermittent: application; of?

pressure to theylefthand side ofpiston'wiwhenthe brakes are. applied. only: balances the-presa cumstances' can-be released until the-legs=are-in fullyoperative'position." I

- The trailer is left-in. the condition: now de'-- scribecl, Removallof thefkingpin haslocked slider. 65;, forward (by, lock 92 a) anda the sup? porting legs; in theinoperative. position: Continned: pressure; from. tank I 2.6.: holds the; brakes set and also holds the-supporting legs inoperafive-position, Ifthe; trailer stands, solong that operating pressure has leaked from tank. I 26'; the supporting legs are still locked by 82a until the king pin is. subsequently. reinserted and locked inplace. v a

To pick up the trailer again andmake ready to .dri've it away, theoperator needs-only to back the truck. under the trailer, and the king pin into place; in the'usual manner; andthe'n couple up the hoses. The a'ctfof backing the king pin into' place autorii'aueauyr 1ocks the king pin' and unlocks the "interlocking slider 68.? so: that. the supporting legs can then be moved. rearwardly. and upwardly to their inoperative positions. However; f or thetimebe'i'rlg; the supportinglgs sure on.-the piston.- .T-he-pressure attheleft-handside of; the-piston never tends positively to/moyer the supporting legsdowrruntil and. unlessrpresfsure is exhausted from supply line; Isllg; an-dzthatpressure is normally-never exhausted exceptwhen the trailer is uncoupled. I I I The application of our improved systemtouse with a vacuum (sub-atmospheric pressure),- operated brake system is I indicated-1 diagrams matic'ally;in.F'ig..11'. Parts which are. the same as those shown in. Fig. 10. are; indicated. lo ythe same numerals, analogous partsbeing indicatedby. like numerals with the sufiixi b The opera. tion of the vacuum systemis1substantially the same .as that ofjth e. pressure system; except that,

the parts are controlled by pressures. less than atmosphere ratherv than greater thanlatmosphere; Thevacuurn supply line H 'lbruns..tlirougli.check, valve [255 and to triple valv' I211) Vacuum ser'vic'elin'ej IZObruns' to valve I2lb'i attheri'ght hand, side of diaph'ragin [3017. As 1ong asit'lie brakecontrol valve'oi'i the truck is set. to main, tain' vacuum. in line I266, the n'iov'able, valve l 3 I b. is held in a position to connect atmospheric." port, I3'2b'with' the une or lines I282), which; go to vacuum, chambers I [2b,v and the brake'fods Illb are releasedfjto release the' brakes; the brake line [2811' a" branch or connecting lirie port I33 (see Fig;

I280 goes to the right hand end ofcylinder Mb.

I Theleft hand end of cylinder I4Ib is connected I ton 40b. Piston 40b, pistonrod 39b and cylinder Mb, bear the same relation to the supporting legs as that shown inFig. l forthe cylinder and piston which has been previously explained.

With the brake control valve set to release the vacuum operated brakes, atmosphere is presentat the right hand side of piston 40?) and tends to hold the supporting legs up because of the vacuum present at the left of the piston. When the brake control valve is set to I relieve the vacuum in service line I2Db,,va1ve spring I35b moves valve I3Ib to the left, cutting off atmosphere port I32band moving valve port I320 into register with vacuumport I331), and therbyap plying vacuum to the brake lines I28bandthe cylinder line I280. As a result," every time the brakes are applied, vacuum is simultaneously applied to the right hand side of the supportoperating piston 40b. However, as long as vacuum is being applied to the left hand side of I the piston, application of vacuum toits right hand side merely balances the pressure and does not tend positively to move the supporting legs down; and, moreover, the supporting legs are positively locked against downward movement I by themechanical lock which hasbeen previously explained.

- Itwill be seen, that the vacuum actuated system operates in fundamental essentials in the normal pressure is also fed through connecting line I20d to the triple valve at the right-hand side of its diaphragm I39 (see Fig. 10) to hold the valve in the left-hand position shown in Fig.

10 and thus to cut o-ffpressure from thebrake chambers and from the left-hand end of cylinder 1 When Md, and to apply atmosphere thereto. pressure is reduced in the control line Hid, or

1d, the reduction ofpressure at the righthand side of the diaphragm allows the triple coupler, in the same manner as before described. 3

The cooperative functions of the complete system of which Fig. 12 shows apart, are the same as that which has been described in connection with Fig. 10. The only substantial structural difference is that there is here but a single Connectingline between the truck and trailer; but the whole system of cooperative inter-action is the same as before described. t I All of the systems which have now been so far described'have included asone featurethe actuation of the trailer-support by thesame power medium that actuates the trailer brakes, and also have included the cooperative actuation of the support and brakes. In certain of the broader aspects of our invention it is not necessary that the same manner as the pressure operated system.

The functions of the Whole cooperative and interlocked system of parts are the same, and the same operations and actuationstake place under control of the operator as hereinbefore described. As is indicated by the foregoing, the term fluid pressure as used herein and in the following definitions of our invention unless otherwise qualified is intended to include both super-atmos- .pheric and sub-atmospheric pressure.

.Fig. 12 illustrates how the supporting leg and the brakes maybe cooperatively actuatedwith only a single fluid pressure connection between the truck and. trailer. In this case the system is illustrated as being actuated by pressure above atmosphere. Here the single line I I5d on the truck is. a combined pressure supply and control line,

connected via coupling H6 and hose I22 to line I I Id on the trailer. Line I IId runs through check;

valve I25Z to tank I26d and to the initial pressure port of triple valve I2'Id which is here illustrated as being the sameiin structure and function as that illustrated in Fig. 10. Instead of the'tri-ple valve being controlled bya separate control line, as in Fig. 10, the control connection. in Fig. 12 comprises the. lineI20d which con-; nects line Id at a point ahead of check valve I25d, with the right-hand end-of control valve I2'Id. Lines I28Id connect the left-hand .end of the triple valve with the brake chambers HM, and the line I28d connects the left-hand end of the triple valve to the left-hand end of cylinder I Md. A line I lie permanently connects the righthandend of cylinder 4|d with the combined I pressure supply and control line I Hot at a point ahead of checkvalve. I25d.

With normal pressure present in line I I'Id, that pressure is fed to tank IZIid and to the pressure 10) of the triplevalve. The 75 If fluid pressure actuation of the brakes is used, that fluid pressure system may have its own trailer support be actuated in cooperation with e the brakes, orthat the power medium for the support and brakes be the same. The trailer support may be actuated by any suitable and independent power medium.

I 'Fig." 13 .forinstance shows howhthe supp ort omit the brake connecting and operating parts I28dfand NM. The action of the triple valve I211 being the sameas before described, it will be seenthat the actuation and control of the legoperating piston 48], through its independent supply and control line I I5 andI Ilf, is the same as has been described inconnection with Fig. 12.

Further, in connection with Fig. 13, the brake system for the trailer may be actuated and con-H trolled in anydesired manner and by any suitable power, as for instance by any conventional fluid pressure or electrical or mechanical system.

individual tank on the trailer, or it may utilize the sametank I2Bf which is utilized inthe support-operating and control system.

The system of Fig. 13, when applied to he trailersupport and the trailer support interlocked with the draftcoupler as in the manner before describedoperatesin allessentials like the complete system which has been described in connection with Fig..10 or-Fig. 12, except that the brakes are not cooperatively actuated and controlled with the trailer support. The trailer support is W? ever actuated and controlled in the samemaner; the support being raised by applying pressure to line .I I1 and exhausting pressure from the left-hand end of cylinder llf by the action of.

and the supporting legs the triple valve 321); and; the. supportbeing; lowered; by; lowering or 'exhaustingrpressure from. line ill-f, eitherby. valvularcon-trol, on. line M!- or by: breaking the-coupling at, us.

Figs. 14 and show illustrative electrical. means for operating the trailer support, which electrical means may be independent of -brake. operation and control. The electrical systems shown in these figuresare to be taken. only as indicative, as many differentcircuitings may, be: devised to accomplish the same-.function.

In Fig. 14, which is more or-less diagrammatic;

' the pivoted supporting legisshown. at 3| 0. and:

the leg supporting links at 340; and. 350.- The connecting rod which interconnects. with the mechanism for interlocking with th coupler is. shown at 700. All. these parts are shown subs stantially the same as. before. described, and are intended to-cooperate with the interlock mechanism and. the coupler as before. described. An electric motor for operating the support up and down is shown at 200,,driving1y connected; with pivoteddink 3-50 through such gearing as shown. at Current for operating the electrical system is derived from any; suitable source 0n,truck. 20,. Via cable 202 and. a- 'disconnectible. coupler 203. From the coupler currentis supplied to. the twomain power leads 204.and 205 on the trailer which lead directly to the two arms of a three. pole reversing switch 206, wire 205' leading. through a relay switch. magnet201h The relay switch 208 is designed tolbe open. when, magnet. 201' is deenergized and'closed whenthe magnet is energized. From lead wire 205 a branchwire 209 leads through relay switch20 to one. of the O position shown .in dotted lines:

' opensbecause of cessation of flow in lead 205,.and=

windings, say the field of motor 200.; and wire.

2|0' leads back from thatsame winding to the other mainpower lead 204. That winding of the motor will thus only beenergizedwhen. relay switch 208 is closed, Which occurs only when magnet 20'! is energized by flow of current through line 2.05 and reversing switch 206i The three contacts 2| l', 2l2 and 2'I3Jof the reversing switch are connected as follows. The middle contact 212 is connected by wire 2l4 to one'side of'the other windin (say the armature) of motor" 200; Wire 2l5 connects the other side of that samewinding with branch wires 2l6 and 2H which lead, respectively, to one side of two normally closed switches 218 and 219. These twoswitches H8 and 219 are physically arranged so' thatswitch M8 is' adapted to be opened when the supporting leg is in its uppermost position. Forinstance, the swinging link 350* may engage switch 2l8 at the end of its upward travel as shown in dotted lines to: open the switch. like; wise switch 2| His arranged to beopened whenthe supporting leg is=inits loweredor operative position. Fig. 14 shows the supporting leg in its latter mentioned position with switch 219 open. I

From the other side of switch 218 a wire- 2.20! leads to contact 2'l3 'of reversin switch 206; and; from the other sideof switch2 |9 a wire 22lleads to-the. third contact 25! I. of" reversing. switch. 206'; Reversing switch 206. may be: either adapted for manual actuation or for actuation cooperaa tively with any other part of; the mechanism which may be desired, for. instancewith the locking lever 80 of the interlock mechanism. The operation will. be described as forv manualaopera tion of switch 206. In. Fig. 14. the switch isshown. in its position to causen'aisingofthetrailer sup port. In that position a. circuit; from. the. main. power leads 2.04 and. 205?- is. completed tdoneof.

1 the circuit to' the other-motor winding is broken- To. lower the, trailer support, switch 2061s, thrown .to itsother position, Where its arms make. contact with contacts 2 and 2l2. The circuit. to: the first mentioned motor winding (armature) then. proceeds from contact 2l2 via wire 214,. and thence from the motor via wires 2 l 5 and wire 2| 1.- to. switch 2i9,- which is now closed. From. switch 218 the circuit is completed via wire 22l back to contact 2 H of the reversing switch. Flow.

, of. current in lead 205-again closes relay switch.

208, and the circuit is completed to the other. motor winding (field) as before. of current feed. to the. first mentioned winding; is. now in. a. reverse direction, and. asv a consequence motor 200rotates in a. direction to lower the trailer support. When the support reachesits. fully lowered. position, switch H9 is. opened, breaking the motor circuit at that point, and. causingthe circuit. to the other. motor winding to be opened at relay switch 208.

In cooperation with the remainder of thedescribed mechanism+-the coupler, the interlock. between the support and. the coupler, and the. manually operated locking handle Gil-this last described form oisupport operating mechanism operatesmuch the same as before described. The support cannot be lowered until the lock operated by, handle to. has been released. It also'cannot be lowered except while the coupling. at 203' is. connected, as the power for operating the leg is derived through that coupling. Consequently the leg cannotbe lowered except when thetractor'is fully .coupled' with the trailer. is lowered; then the coupling at 203- may be disconnected and the tractor pulledawa-y' from the trailer; Incoupling up,- the-supporting leg cannot be-raised until the tractor-has'b-eenlocked-to ie trail'er, becauseof the interlock mechanism before described. 1 Also the legcannot beraised' until coupling 233'! has been-coupled up: Whenthat; is. done then the. operator may raisev the supporting leg by throwing switch 206. to. its; proper position.

Fig; 15.;sh0ws. another,- form of electrical operae tionoi thetrailersupport, which is actuated. and:

controlled by, virtue of coupling and uncoupling.

the; electric coupling. between the; tractor. and) trailer; In;this figure thesupporting legandits pivoted operating. links; are: designated by the samenmnerals as in Fig. 14.. i I

Current; for. control .of the,-electricallyi operated mechanism is obtainedfromthe tractor-from any, suitable.source,v as-froma batter 400, under. con trolof switch 40!, if, desired. And disengageable coupler- 492i connects the trucklinesor cable. 403.- with theicontrol linesAllt-on the trailer. Circuit 604 leads to relay switch magneti405, energization, of whiclrmoves the reversing switchMlG: to theposition-shown in .Fig. 15.. In this positionof. the reversing.and controllingswitch.406 the sup.-

The direction Once the support the relay magnet 4 IZWhen that magnet is energized. Magnet 4 I2 is includedin the circuit comprising wire M3 and branch wires 4 and M5 which lead respectively to the two normally closed switches 4H; and 4|! whichare similarin placement and operation to the two switches H8 and 219 of Fig. 14. From switch4|6 a wire 4201eads tocontact 42! of control switch 406; andfrom switch 4|] a wire 422 leads to contact 423 of control switch 406. The center contact 424 of the control switch is connected by wire 425 to battery 408. i i

In the switch position shown inFig. 15, motor 401 is energized toraise the supporting leg. In

the lowered position of the leg switch M6 is open and switch 4H closed. Current flows from the battery through wire 425 and center contact 424 of switch 406 and thence to movable contact 426 and via wire 421 to the motor armature winding; and thence via wire 428 to the other movable switch contact 429, and through. switch contact moved up and down unless the truck is draftconnected with the trailer and the coupler locked,

andalso unless the coupling at 402, or its equivalent switches, are manipulated. And further,

similar to the operation in those other figures,

breaking of the coupling at 402 automatically.

causes the supporting leg to be lowered; and the supporting leg cannot be raised until the truck is untilthe coupling 402is closed.

fully draft-connected with the trailer and also Fromwhat has been said regarding thaform of Fig. it will berecognized that the line coupling of 402 ultimately controls the release of the draft coupler. Breaking. the power supply at that coupling causes the lowering of support 3l0,

and, as. has been explained, the draft coupler cannot be openeduntilthe supportis lowered.

The condition of thecoupling (whether made or broken) controls the release of the draft coupler,

through a'm'echanism which comprises the support actuating devices and the interlock devices which act between the support and the draft lock. The action of that chain ofmechanism is 423and wire422, switch 4l'i,wire 415, and wire 4I3and relay-magnet M2 to thebattery; Energization of magnet 4l2 closes the field circuit of the motor, and the motor rotates in a direction to raise the supporting leg. When thesu'pporting leg reaches its upper position, switch 4!! opens, breaking the armaturewinding circuit and deenergizing relay magnet M2 to break the field winding circuit. Thus, whenever relay magnet 405 is energized, as by engaging the coupling at 402 or bymanipulation of acontrol switch on the tractor, or a controlswitch such as indicated by 404a on-the trailenthe supporting leg will be raised from its lowered position to its upper inoperative position. i I

By deenergizing the relay magnet 405 by any of the control means, or by breaking the coupling at 402, the two movable contacts of control switch 406 go to their other positions, to make contact with stationary contacts 42 I and 424. In that position of switch 406 current from battery 408 flows through 425; contact 424 and contact 429, wire 428, the motor armature winding, wire 421, contact 426, contact 42!, wire 420,-switch 41.6 (which is the-n closed, the leg being up) and wires 4 I4 and M3 back to the battery. The mo-. tor field winding circuit is closed as before explained, and the motor now rotates ina direction to lower the supportingleg; the motor circuit beirig broken at the end of the operation by switch 4l6being opened. I e U The supporting leg being interlocked withthe coupler mechanism-by bar100, the overall operation and functions of theform shown in Fig. 15

. are similarto that of the forms first explained,

such that the draft lockis released as a result 51 of breaking the coupling 402; and the draft lock is held closed whenever coupling 402 is made,

because the immediate result of making coupling 1 402 is to raise} the support and hold it raised, and therefore; through the interlock, to hold the draft coupler closed,

The same functions are inherent in the forms first described; for instance that of Fig. 10. As has beenexplained, as longas the support is up the draft lock is held closed by the interlock.

The support is causedto move down by the unbalance of forces. on the support actuating motor when coupling I [6, or both couplings I I6 and H9,

; arebroken. Until that occurs the draft coupler and to that of theforms explained in connection with Figs. 12 and 13. As in Figs. 13 and 14, the

operation of the supporting leg of Fig. 15 may be independent of thebrake operation; but as in Figs. 10,11, 12 and 13the operation of. the leg in Fig. 15 is under control of coupler 402 which couplesthe source of energy on the truckwith the trailer. If switches 40! and 404a are omitted or kept closed, the operation of the leg is completelyunder control of coupling 402. Thus, as

has been explained in connection with those other.

figures, the trail'ersupport of Fig. 15 cannot be isheld'closed; when it occurs the draft coupler;

is released. Thus, in the pressure actuated forms .the condition of the coupling, whether madeor.

release.

r We claim: l x l l e 1. In a tractor and semi-trailer combination in which the tractor and trailer are provided with interengaging draftelements including a releasable draft lock operable to lock the two vehicles broken, has ultimate control of the draft lock together, in which the trailer is provided with a support actuatable between supporting and nonsupporting conditions by an operatingme ans independent of the tractor draft element, and in which the traileris provided with a brake system of the type involving a pressuresupply and contro-l line means wherein pressure variations cause application of pressure to brake actuating mechanism to set the brake; the combination of, means for actuating the supportincluding a motor element adapted to be pressure actuated in either of two directions, means whereby pressure exist- I ing in theline means tends to cause m'otor operation in a direction to actuate the support into nonsupporting condition, and means whereby brake setting pressure existing in the brake actuating mechanism is applied to the supportactuating motor to causemotor' operation in a direction to actuate the support into supporting condition. y

*2. In a semi-trailer adapted to be coupled to and supported on a tractor, the semi-trailer being provided with asupport actuatable between supporting and non-supporting condition, and also being provided with a brake system of the type. involving a power supply and controlline means wherein power variations cause application of power tobrake. actuating mechanism to set the brake; the combination of means for actuating the support including a motor element adapted to be power actuated in either of two directions, means whereby power existing in the line means tendsto cause motor operationin a direction to actuate the supportinto non-supporting condition, and means whereby brake setting power applied to the brake actuating mechanism is also applied to the support actuating motor to cause motor operation in a direction to actuate the support into supporting condition.

' 3. In a tractor and semi-trailer combination in which the tractor and trailer are provided with interengaging-draft elements including a releasable draft lock operable to lock the two vehicles together; in which the trailer is provided with a support actuatable between supporting and nonsupporting conditions by an operating means which .is independent of the tractor draft-element, and in which the trailer is provided with. a brake system of the type involving a pressure supply line and a control line wherein pressure variations cause application of supply line pressure to brake actuating mechanism to set the brake; thecombination of means for actuating the support including a motor element adapted to be pressure actuated in either of two opposite directions byfluid pressure, a fluid pressure connection between the pressure supply line and the motor in such manner that pressure existing in the supply line tends to cause motor operation in it a direction to. actuate the support into non-supporting condition, and a fiuidpressure connection.

between the brake actuating mechanism and the support motor in such manner that brake settin engaging draft elements including a releasable pressure existing in the brake actuating mechanism is applied to the support motor to cause motor operation in a direction to actuate the support into supporting condition. y

4. In. a semi-trailer adapted; to be coupled to and'supported ona tractonthe semi-trailer being provided with a support actuatable between supporting and non-supporting condition, and also being provided with abrakesystem of the type involving a power supply line and a control linefwherein power variations cause application of" the supplyl-ine power to brake actuat- 1'3 mechanism to set the brake; the combinations of means-for actuating the support including, a motor element adapted to be poweractu ated in, either of two opposite directions, a power connection between the power supply line and the motor in such manner that power existing in the supply line tends ,to causeimotor operation in a direction to actuate thesupport into non-supporting condition, and a power connection bee tween the brake actuating mechanism and the supportmoto-r in such manner that brake setting power existing in the actuating mechanism is vap lied to the support motor to cause motor operation in a direction to actuate the support intosupporting condition.

5. In a combination which includes two intercoupled vehicles which are provided with interengaging draftelements including a releasable draft lock operableto lock. the two vehicles together, and a power transmitting line leading be. tween the two vehicles and having a coupling which is connectibley. and disconnectible; between controlled in dependence on one ofthe positions of said means for e fiectingr the release of the draft lock. r

6.- In a combination which includes two intercoupled vehicles which are provided with inter draft lock operable to lock the two vehicles to.-

gether, and a power transmitting line leading between the two vehicles and having a Coupling which isconnectible and disconnectible between them to allow separation of the vehicles; the improvement 1 which comprises 7 means assuming one orthe other of two positions in response to the condition of connection ordisconnection of the power line coupling, and operating means controlled in dependenceon one'of the positions of said means for holding the draft lock. closed whereby. the draft lock is releasable only in dependence on the other said means. H I I 7. 'In a combination whichincludes two intercoupled vehicles which are provided with inter:

engaging draft elements including a releasable draft lock operable to lock the two vehicles together, and a power transmitting line through which power is supplied from one vehicle to the other and which is connectible and disconnectible between the vehicles'to allow their sepa ration; the improvement which comprises means assuming one or the other of two-positions in response to the condition of existence or nonexistence of power in the line, and operating means controlled independence on one of thepositions;

of said means for effecting the release of the draft lock. r

a 8. In a combination which includes'vtwoin-tera coupled vehicles which are provided with inter-- engaging draft elements including a releasable:

draft lock operable to look' the two vehicles tol gether, and a power-transmitting line through which, power is suppliedfrom one vehicle to the other and which is connectib-le and disconnectible between the vehicles to allow their sepaep ration; the improvement which comprises, means assuming one orthe other of two positions. in response to the condition of existence or nonexistence of. power in the line, and operating means. controlled in dependence on one of the them to allow separation of the vehicles; the

the condition of connection or disconnection of the power line coupling and operating means.

. only independence on t positions of said means for holding the draft lock closed whereby the, draft lock; is releasable he other of the positions of said means. i

9'. In a tractor and semi-trailer combination in which the tractor and trailer are providedwith inter-engaging draft elements including a. re-- leasable draft lock operable to lock the two vehicles together, in which the trailer is provided with a supportactua-table between supporting and non-supporting conditions by an operating means which is independent of the tractor draft element, and in I which the trailer is provided with a brake system of the type involving aipresf-F sure supply line and. a, control line wherein pres.-.

sure variations cause application of supply line. pressure to brake actuating mechani'smto-v actu;

ate it; said lines leading fromc'the'tractor to the trailer and being d-isconnectible to, allow theirseparation; the; combination of means. for actuf-* ating the support including a. motor element adapted to be actuated in either of two opposite directions by fluid pressure; a. fluid pressure" connection between the fluid supply line and themotor in such manner'that pressure, existing in h s pp y ine tends to. causemotor operation in a d r c on t actuate the support into. non-supof the positions. of

porting condition, and a fluid pressure connection between the brake actuating mechanism and the support motor in such manner thatappli-,

, cation of actuating pressure to, the brake mechwhereby the support is locked in supporting condition by virtue of the draft lock being unlocked.

10. In. a tractor and semi-trailer combination in which the tractor and trailer are provided with interengaging draft elements including a releasable draft lock operable to lock the two vehicles together in which the trailer is provided with a support actuatable between supporting and nonsupporting conditions by an operating means which is independent of the tractor draft element, and in which thetrailer is provided with a brake system of the type involving a power supply and control line means wherein power variations cause application of supply line pressure to brake actu-- ating mechanism to actuate it, said line means extending from the tractor to the trailer and beingdisconnectible toallow their separation; the combination of means for actuating the support including amotor element adapted to be power actuated in either of two directions, means whereby power existingin the line means tends to cause motor operation in a direction to actuatethe support into non-supporting condition, and means whereby application of actuating powerto the brake mechanism tends to cause motor operation in a direction to actuate the l support into supporting condition, means wherel by the draft lock is' held in locked condition selectively by virtue of the support being innonsupporting condition, so that the draft lock is releasable onlywhen the support isin supporting condition, and means whereby the support is locked in supporting condition by virtue of the draft lock being unlocked.

11. In a tractor andsemi-trailer combination in which the tractor and trailer are provided with interengaging draft elements including a releasable draft lock operable to lock the two; vehicles together, in which the trailer is provided with a supportactuatable between supporting and non-supporting conditions by an operating means independent of the tractordraft element, and inwhichthe trailer isprovided with a brake system of the type involving a power supply and control line meanswherein power;

, variations cause application of power to brake actuating mechanism to actuate it; the combination of means for actuating the support including a motor element adapted to be actuated in either of two directions, means whereby power existing in the line means tends to cause motor operation in a direction to actuate the support into non-supporting condition, and means whereby application of actuating power to the brake mechanism tends to cause motor operation in a direction to actuate the support into sup porting condition, manual means normally looking the support in non-supporting condition, said means being manually settable to release the support, and re-settable by movement of the support to subsequently automatically lock the support upon its subsequently reaching its nonsupporting condition, means whereby the draft lock is held in locked condition by virtue of the II! support being in non-supporting condition, and means whereby the support is locked in supporting :condition by virtue of the draft lock being unlocked. 12. In a tractor, and semi-trailer combination in which thetractor and trailer are provided with interengaging. draft elements including a releasable draft lock operableto lock the two vehicles together, in which the trailer is provided with: a support actuatable betweensupportingand non-supporting conditions by an operating means which is independent of the tractor draft element, and in which the trailer is provided with a brake system of the type involving a pressure supply line and a control line whereinpressure variations cause application of supplyline pressure to brake actuating mechanism to actuate it; thecombination of means for actuating the support including a motor element adapted to be actuated in either of two opposite directions by fluidpressure, a fluid pressure connection between the fluid supply line and the motor such manner that pressure existing in the supply line tends to cause motor operation in a direction to actuate the support into non-supporting condition, and a fluid pressure connection between thebrake actuating mechanism and the support motor in such manner that application of actuby movement of thesupport to subsequently automatically lock the support upon itssubsequently reaching its non-supporting condition, means whereby the draft lock is held in locked condition-b-y virtue of the support being in nonsupporting. condition, and means whereby the support is locked in supporting condition by virture of the draft lock being unlocked.

13. In a tractor and semi-trailer combination in which the tractor and trailer are provided with interengaging draft elements including a releasable draft lock operable to lock the two vehicles together, and in which the trailer is provided with a support actuable between supporting and non-supporting conditions by an operating means which is independent of the. tractor draft element; the combination of an interlock mechanism interposed between the draft lock and the support and acting to hold the draft lock in locked condition whenever the support is in non-supporting condition, and actingto look i the support, in supporting condition whenever the draft look is unlocked, and manu ally releasable means,- in addition to the interlock mechanism, associated with a part which moves the support and adapted normally to lock the support in non-supporting condition.

14. In a tractor and semi-trailer combination in which the tractor and trailer are provided I element, the combination of an interlock mechanism interposed between the draft lock and the support and acting to hold the draft lock in locked condition whenever the support is in non-, supporting condition, and acting to lock the support in supporting condition whenever the draft tion.

'15. In a tractor and semi-trailer Combination .in which the tractor and trailer are provided with interengaging draft elements includin'g a releasable draft lock operable to lock the two veicicles-together, and in which the trailer is provided with a support actuatable between supporting and non-supporting conditions by an operating means which is independent. of the tractor draft element; the combination of an interlock mechanism interposed between the draft lock and the support and acting to hold the-draft lock in locked condition selectively whenever the support is in non-supporting con dition,.so that thedraft lock is releasable only when the support is in supporting condition, power actuated means for causing movement of 'the support between supporting and non-supporting conditions; a power transmitting line leading from the tractor to the trailer and disconnectible to allow separation of the two vehicles, and means whereby disconnection of the line causes operation of the power actuated vmeans to cause movement of the support to supporting condition.

' 1.6. In a tractor and semi-trailer combination inwhichv the tractor and trailer are provided with interengaging draft elements including a releasable draft lock operable to lock the twovehicles together, and in which the trailer is.

provided with a support actuatable between supporting and non-supporting conditions by an operating means which is independent of the tractor draft element; the combination of an interlock mechanism interposed between the draft lock and the support and acting to hold the draft lock inlocked condition selectively whenever the support is in non-supporting condition, so that the draft lock is releasable only when the. support is in supporting condition, and to hold the support in supporting condition whenever the draft lock is unlocked, power actuated means for erati'on of the power actuated means to. cause movement of the support respectively to its nonsupporting and its supporting conditions.

1'1. In a tractor and semi-trailer combination in which the tractor and trailer are provided with interengaging draft. elements including a releasable draft lock operable to lock the two. vehicles together, and in which the trailer is provided with a support actuatable between supporting and non-supporting conditions by an operating means. which is independent of the tractor draft element, and in which the trailer is provided with power actuated brakes; the combin'aiaon of power actuated means for causing movement of the support between supporting and non-supporting conditions, brake-power.

controlling line leading from the tractor to the in which the tractor and trailer are provided.

with interengaging draft elements includinga releasable draft lock operable to lock the two vehicles together, and in which the trailer is provided with av support actuatable between; supporting and non-supporting conditions by an operating means which is independent of the tractor draft element, and in which the trailer is pro vided with power actuated brakes; the combination of power actuated means for causing move: ment of the support between supporting and non-supporting conditions, brake-power controlling line leading from the tractor to the trailer and disconnectible to allow separation of the two vehicles, means whereby connection and dis-connection of the brake-power controlling line causes operation of the power actuated means to cause movement of the support respectively to its non-supporting and supporting conditions,

and interlocking meansv acting between the draft causing movement of the support between supporting and non-supporting conditions, a power transmitting line leading from the tractor to the trailer and disconnectible to allow separation of the two vehicles, and means whereby connection and disconnection of the line causes oplock and the support to hold the draft lock in locked condition selectively whenever the support is in non-supporting condition, so that the draft lock is releasable only when the support is in supporting condition, and acting to hold the support in supporting condition whenever thev draft lock is unlocked.

- ROBERT M. BARNHART.

JAMES S.. TORMEY.

CERTIFICATE OF ccRREcT oNQ Patent No. 2,565,851. November 2 19th.

ROBERT M. BARNHAR'I, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 11, sec ond co lumn, line 60, claim 15, after the word "moves" insert --with-'---; and that the said Letters Patent should be read with this correction therein that the same may conform to the record oithev case in the Patent Office.

Signed and sealed this 20th day of February, A. D. 1911.5.

Leslie Frazer (Seal) Acting Commissioner 'of Patents 

